I have a 2007 2 wheel drive Titan that has a pulsating slight vibration feel at and above 60 MPH. I don't hear a noise. The faster I go the more pronounced the pulsating. The frequency of the pulsating is once every 2 seconds or so. I feel it in the steering wheel and the floorboard. Any idea as to what it is?
Assuming that you're stock-ish/not lifted, it sounds to me like something is just out of balance. How many miles on your current wheels/tires? Have they been rotated regularly? If you have a lot of miles on the tires, consider getting the wheels rebalanced. Lastly, if none of that works, I'd check your brake rotors to make sure they're not warped.
In my experience, if an increase in speed leads to an increase in vibration, the problem usually lies with rotating mass (aka wheels, tires, brakes, driveshaft, etc). Not always, but more often than not. Also, the fact that you're feeling it in the steering wheel implies that it's something in contact with or close to the road, so that should help narrow it down a bit.
Good luck!
